Refrigerator including defrost means



July 30, 1968 G. D. JONES REFRIGERATOR INCLUDING DEFROST MEANS FiledSept. 8, 1967 MM 4 F 2 G 4 2 l n d II W a :l, 1 o\ R x U U M l-usATTORQEY United States Patent G 3,394,559 REFRIGERATOR INCLUDING DEFROSTMEANS Gary D. Jones, Louisville, Ky., assignor to General ElectricCompany, a corporation of New York Continuation of application Ser. No.490,930, Sept. 28, 1965. This application Sept. 8, 1967, Ser. No.672,410 6 Claims. (Cl. 62--276) ABSTRACT OF THE DISCLOSURE Arefrigerator including a housing containing an evaporator and a radiantheat defrost means mounted below the evaporator for servicing through anair passage in the front wall of the housing. Means are provided toprevent heat radiating from the defrost means to the refrigeratorcompartment.

This is a continuation of application Ser. No. 490,930, filed Sept. 8,1965, now abandoned.

The present invention relates to household refrigerators and is moreparticularly concerned with a refrigerator including an evaporatorstructure comprising a radiant heater for periodically warming theevaporator to defrosting temperatures.

Many modern refrigerators include electric resistance heaters forperiodically raising the temperature of the evaporator to defrostingtemperatures. The heaters are generally mounted in direct heatconducting relationship with the evaporators and are frequently embeddeddirectly into the fin core structure thereof. When the heater fails, itsreplacement is an expensive procedure and frequently the entireevaporator structure must be replaced.

An object of the present invention is to provide a refrigeratorincluding an evaporator adapted to collect frost during normal operationthereof and improved, low cost means for periodically warming theevaporator to defrosting temperatures.

Another object of the invention is to provide in a defrostableevaporator structure, radiant heater defrost means which is separatefrom the evaporator component of the structure so that it can be readilyserviced or replaced.

Further objects and advantages of the invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In accordance with the illustrated embodiment of the present invention,there is provided a household refrigerator including a storagecompartment and an evaporator unit within the compartment. The unitcomprises a housing including a front wall having at least one airpassage therein communicating with the compartment. An evaporator whichnormally operates at frost collecting temperatures is contained withinthe housing. For the purpose of periodically defrosting the evaporator,there is provided radiant heater defrost means also positioned withinthe housing below the evaporator and in an accessible position adjacentthe air passage. To shield the contents of the storage compartment fromradiant heat during operation of the heater, a shield is providedbetween the heater and the air passage. In accordance with the preferredembodiment of the invention, the housing is so designed that the radiantheater can be removed from the housing through the air passage and tothis end the air passage is in the form of a slot extending the fullwidth of the front wall of the housing while the adjacent side walls ofthe housing are provided with slots communicating with the air passageand adapted to support the opposite ends of a radiant heater inoperative position relative to the evaporator.

For a better understanding of the invention reference may be had to theaccompanying drawing in which:

FIGURE 1 is an elevational view partly in section of a portion of arefrigerator cabinet embodying the present invention;

FIGURE 2 is a front elevational view of a portion of the evaporator unitor structure forming part of the refrigerator of FIGURE 1; and

FIGURE 3 is a vertical sectional view taken generally along line 33 ofFIGURE 2.

Referring now to the drawing, there is illustrated a refrigeratorcabinet of the two temperature type and including a freezer compartment1 and a fresh food storage compartment 2. The freezer compartment 1 isprovided with a drawer structure generally indicated by the numeral 3for the storage of frozen foodstuffs.

For the purpose of maintaining the contents of the freezer compartment 1at below freezing temperatures there is provided an evaporator unit 4supported along the rear wall of the freezer compartment. Thisevaporator structure comprises a housing 5 including a front wall 6,opposed side walls 7 and a sloping generally V-shaped bottom wall 8. Afin-on-tube evaporator 9 is contained within the housing 4 intermediatethe top and bottom ends thereof.

In order to cool the contents of the freezer compartment 1 tosub-freezing temperatures, air from the compartment is circulatedthrough the housing and over the evaporator 9. The illustrated aircirculating means includes an inlet air passage 11 in the lower portionof wall 6 and a second air passage 12 in the upper portion of the Wall6. The evaporator 9 is generally disposed within the housing betweenthese two air passages. A motor driven fan 14 adjacent the upper airpassage 12 provides means for drawing air from the freezer compartmentinto the housing through the air passage 11 and this air after passingupwardly between the fins 15 forming part of the evaporator 9 isdischarged from the housing through the air passage 12. The evaporator 9forms part of a refrigeration system including a compressor 10 and acondenser (not shown) by means of which condensed or liquid refrigerantis fed to the evaporator.

During operation of the evaporator at below freezing temperatures,moisture contained in the air circulated from the compartment 1 throughthe housing tends to collect as frost on the evaporator and particularlyon the lower portions of the evaporator adjacent the air inlet passage11. In order to periodically warm the evaporator to defrostingtemperatures, there is provided heating means in the form of tubularheater 16 extending transversely of the housing below the evaporator 9.This heater comprises a tubular member 17 of quartz or similar glasslikeinsulating material such as Vycor having good thermal shock and radiantheat transmitting properties and a heater coil 18 within the tubularmember 17. Such heaters are so designed that a substantial portion ofthe heating is by radiation although convective heat transfer may alsobe an important factor.

The radiant heater structure also includes at the opposite ends of thetubular member 17 end caps 19 for closing the opposite ends of thetubular member 17 and terminal members 20 for connecting the oppositeends of the heater coil 18 to a source of electric power.

In order that the heating means 16 be readily accessible for repair orreplacement purposes, the air inlet passage 11 extends the full width ofthe front wall 6 of the housing and the end walls 7 of the housing areprovided with slots 23 extending rearwardly from the passage 11 anddesigned respectively to receive and support the end caps 19 on theopposite ends of the radiant heater structure 16. By this arrangement,the radiant heater structure can be inserted into or removed from thehousing through the air passage 11 after first removing an appearancegrille 24 if such is employed as a decorative member overlying thepassage 11.

For the purpose of shielding the contents of the freezer compartment 1from direct exposure to the radiant heat from the defrost heater 16,there is provided a metal shield 25, in the position such that theshield is between the radiant heater and the air passage 11 or in otherwords in a position such that it prevents heat rays from radiatingdirectly to the compartment 1. The ends of the shield 25 may also besupported in slots 23.

It will be understood that the operation of the heater can be controlledby any suitable means. For example, defrosting of the evaporator may becontrolled by a defrost timer which periodically energizes the heatercoil 18 during a period when the compressor is not operating. Variousalternative means of controlling the defrost operation are also wellknown. The defrost water collects in the bottom wall 8 of the housingfrom which it is drained from the cabinet by any suitable means.

From the above description it will be seen that there has been provideda defrostable evaporator structure including a low cost radiant heaterand adapted to'warm the evaporator and the adjacent portions of thehousing including the drain system to defrost temperatures. This heateris located below the evaporator in the most advantageous heatingposition for both radiant and convective heating and is adjacent an areaof the evaporator on which the major portion of the frost collects. Thehousing portion of the evaporator structure is designed not only tosupport the heater or more specifically the end caps thereof but also toprovide easy replacement of the heater in the event that it should fail.As the electrical terminals are outside of the housing 5, they aretherefore not directly exposed to the defrost water within the housingduring defrosting of the evaporator 9.

While there has been shown and described a particular embodiment of theinvention, it is to be understood that the invention is not limitedthereto and it is intended by the appended claims to cover all suchchanges and modifications as fall within the true spirit and scope ofthe invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates:

1. A refrigerator comprising:

a storage compartment,

an evaporator unit in said compartment,

said unit comprising a housing including a front wall facing saidcompartment and means including an air passage in the lower portion ofsaid front Wall and communicating with said compartment for circulatingair from said compartment through said housing,

an evaporator normally operated at frost collecting temperaturespositioned in said housing above said air passage,

radiant heater defrost means for periodically warming said evaporator todefrosting temperatures comprising a tube of insulating, heattransmitting material and a radiant heater coil in said tube, saidradiant heater defrost means being positioned in said housing below saidevaporator and adjacent said passage,

and a shield supported in said housing between said heater and saidpassage for shielding the contents of said compartment from radiant heatfrom said heater during operation thereof.

2. A refrigerator comprising:

a storage compartment,

an evaporator unit in said compartment,

said unit comprising a housing, said housing including a front wallfacing said compartment and having an inlet air passage extendingtransversely thereof,

side walls including slots therein extending rearwardly from the ends ofsaid passage and a bottom wall forming a drain trough, an evaporatornormally operated at frost collecting temperatures positioned in saidhousing, radiant heater defrost means for periodically warming saidevaporator and said drain trough to defrosting temperatures comprising atube of insulating, heat transmitting material and a radiant heater coilin said tube, said radiant heater defrost means being positioned in saidhousing adjacent said passage and having the ends thereof supported insaid slots, and a shield positioned in said housing between said heaterand said passage with the ends thereof supported in said slots forshielding the contents of said compartment from radiant heat from saidheater during operation thereof. 3. A refrigerator comprising: a storagecompartment, an evaporator unit, said unit comprising a housingincluding a front Wall facing said compartment and means including anair passage in said wall and communicating with said compartment forcirculating air from said compartment through said housing, anevaporator normally operated at frost collecting temperatures positionedin said housing, radiant heater defrost means for periodically warmingsaid evaporator to defrost temperatures comprising a tube of insulating,heat transmitting material and a radiant heater coil in said tube, saidradiant heater defrost means being positioned in said housing adjacentsaid passage and in radiant heating relationship with said evaporator,and means for preventing heat rays from radiating directly from saidheater "through said passage to said compartment during openation ofsaid heater. 4. A refrigerator comprising: a storage compartment, anevaporator unit, said unit comprising a housing including a front wallfacing said compartment and means including an air passage in said walland communicating with said compartment for circulating air from saidcompartment through said housing, an evaporator normally operated atfrost collecting temperature positioned in said housing, radiant heaterdefrost means for periodically warming said evaponator to defrostingtemperatures comprising a tube of insulating, heat transmitting materialand a radiant heater coil in said tube, said radiant heater defrostmeans being positioned in said housing adjacent said passage and inradiant heating relationship with said evaporator, and a shieldsupported in said housing between said heater and said passage forpreventing heat rays from radiating directly from said heater to saidcompartment during operation of said heater. 5. The refrigerator ofclaim 4 in which said air passage is in the lower portion of said Wall.

6. The refrigerator of claim 4 in which said radiant heater defrostmeans is positioned adjacent the lower portion of said evaporator.

References Cited UNITED STATES PATENTS 3,063,253 11/1962 Dickson 62-276XR 3,099,914 8/1963 De Witt 62276 3,120,111 2/1964 Simmons 62-276 MEYERPERLIN, Primary Examiner.

